Advancing the effective use of light for society and the environment.

Wednesday, October 13, 2004

LRC studies LED technology for supermarkets
A new project will evaluate LED lighting performance and shoppers’ lighting preferences for grocery store freezer cases.
Photo: Supermarket customer in freezer aisle

The LRC is evaluating light-emitting diode (LED) technology for use in commercial display freezers. The study, funded by the New York State Energy Research and Development Authority (NYSERDA), will evaluate performance, energy savings, shopper preferences, and product sales for this technology compared with the fluorescent lighting currently found in supermarket freezers.

The LRC is collaborating with GE’s GELcore, the Golub Corporation (Price Chopper supermarkets), and Tyler Refrigeration (a division of Carrier Corp.) on this project. The team recently installed a four-door freezer with a prototype LED lighting system in the frozen-food aisle at an Albany, N.Y.-area Price Chopper supermarket.

N. Narendran, Ph.D., LRC director of research, says of the new field study, “To the best of our knowledge, this is the first freezer to operate with advanced white LED technology on a supermarket retail floor.” During the next several months, LRC researchers will survey shoppers about the LED freezer and a similar fluorescent-lighted freezer to determine shoppers’ lighting preferences. Shoppers will evaluate the attractiveness and the clarity of the merchandise within each freezer case. The LRC also will analyze sales data to determine whether the freezer lighting has any influence on consumers’ buying habits. Results will be presented in spring 2005.

Photo: Supermarket freezer aisle

In a prior laboratory study, the LRC developed a prototype refrigerator lighting system using LEDs with the goals of reducing energy usage and producing better illumination for the merchandise. The results showed that the LED lighting system produced more uniform illumination on the displayed products and was strongly preferred by more people than traditional fluorescent lighting in this application. LRC researchers also estimated that when the efficacy of white LED lighting systems reaches 38 lumens per watt, LEDs will use less energy than traditional fluorescent lamps in this application. The efficacy of white LED lighting systems currently stands at approximately 24 lumens per watt and is expected to exceed 38 lumens within two years.

Finding more efficient ways to light freezer and refrigerator cases is important because supermarkets spend nearly half of their electricity costs on refrigeration. Though fluorescent lighting is generally considered energy efficient, these lighting systems do not perform well inside freezers, says Dr. Narendran. “Cold temperatures decrease the light output of fluorescent lamps and, at the same time, reduce their operating life,” he says. The final result is increased power consumption and more frequent maintenance, which impact the overall cost of operating the lamps. Improvements in white LEDs, however, are showing potential for these light sources to have better efficiency than fluorescent lamps. “LEDs are not plagued with the cold temperature problems affecting fluorescent lamps, which means energy and maintenance costs can be reduced in the long run by using LEDs inside freezers,” Narendran says.

About the LRC

The Lighting Research Center (LRC) is part of Rensselaer Polytechnic Institute and is the leading university-based research center devoted to lighting. Founded in 1988, the Lighting Research Center has built an international reputation as a trusted and reliable source for objective information about lighting technologies, applications, and products. Its mission is to advance the effective use of light and create a positive legacy of change for society and the environment.

© 2004 Rensselaer Polytechnic Institute, Troy, NY 12180 USA.

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